Nickel complexes supported by quinoline-based ligands: synthesis, characterization and catalysis in the cross-coupling of arylzinc reagents and aryl chlorides or aryltrimethylammonium salts
作者:Qiang Zhang、Xue-Qi Zhang、Zhong-Xia Wang
DOI:10.1039/c2dt30886j
日期:——
Lithium and nickel complexes bearing quinoline-based ligands have been synthesized and characterized. Reaction of 8-azidoquinoline with Ph2PNHR (R = p-MeC6H4, But) affords N-(8-quinolyl)iminophosphoranes RNHP(Ph2)N(8-C9H6N) (1a, R = p-MeC6H4; 1b, R = But. C9H6N = quinolyl)). Reaction of 1a with (DME)NiCl2 generates a nickel complex [NiCl2N(8-C9H6N)P(Ph2)NH(p-MeC6H4)}] (2a). Treatment of 1b with (DME)NiCl2 and following with NaH produces [NiCl(1,2-C6H4)P(Ph)(NHBut)N(8-C9H6N)}] (4). Complex 4 was also obtained by reaction of (DME)NiCl2 with [Li(1,2-C6H4)P(Ph)(NHBut)N(8-C9H6N)}] (5) prepared through lithiation of 1b. Reaction of 2-PyCH2P(Ph2)N(8-C9H6N) (6, Py = pyridyl) and PhNC(Ph)CH2P(Ph2)N(8-C9H6N) (8), respectively, with (DME)NiCl2 yields two five-coordinate N,N,N-chelate nickel complexes, [NiCl22-PyCH2P(Ph2)N(8-C9H6N)}] (7) and [NiCl2PhNC(Ph)CH2P(Ph2)N(8-C9H6N)}] (9). Similar reaction between Ph2PCH2P(Ph2)N(8-C9H6N) (10) and (DME)NiCl2 results in five-coordinate N,N,P-chelate nickel complex [NiCl2Ph2PCH2P(Ph2)N(8-C9H6N)}] (11). Treatment of [(8-C9H6N)NP(Ph2)]2CH2 (12) [prepared from (Ph2P)2CH2 and 2 equiv. of 8-azidoquinoline] with LiBun and (DME)NiCl2 successively affords [NiCl(8-C9H6N)NP(Ph2)}2CH] (13). The new compounds were characterized by 1H, 13C and 31P NMR spectroscopy (for the diamagnetic compounds), IR spectroscopy (for the nickel complexes) and elemental analysis. Complexes 2a, 4, 7, 9, 11 and 13 were also characterized by single-crystal X-ray diffraction techniques. The nickel complexes were evaluated for the catalysis in the cross-coupling reactions of arylzinc reagents with aryl chlorides and aryltrimethylammonium salts. Complex 7 exhibits the highest activity among the complexes in catalyzing the reactions of arylzinc reagents with either aryl chlorides or aryltrimethylammonium bromides.
含喹啉基配体的锂和镍配合物已被合成和表征。8-叠氮喹啉与Ph2PNHR(R = p-MeC6H4, But)反应得到N-(8-喹啉基)亚氨基膦烷RNHP(Ph2)N(8-C9H6N)(1a, R = p-MeC6H4; 1b, R = But. C9H6N = 喹啉基))。1a与(DME)NiCl2反应生成镍配合物[NiCl2N(8-C9H6N)P(Ph2)NH(p-MeC6H4)}] (2a)。1b与(DME)NiCl2反应后,再用NaH处理得到[NiCl(1,2-C6H4)P(Ph)(NHBut)N(8-C9H6N)}] (4)。配合物4也可通过(DME)NiCl2与[Li(1,2-C6H4)P(Ph)(NHBut)N(8-C9H6N)}] (5)反应得到,后者是通过1b的锂化制备的。2-吡啶基甲基P(Ph2)N(8-C9H6N)(6, Py = 吡啶基)和PhNC(Ph)CH2P(Ph2)N(8-C9H6N)(8)分别与(DME)NiCl2反应,得到两个五配位的N,N,N-螯合镍配合物[NiCl22-PyCH2P(Ph2)N(8-C9H6N)}] (7)和[NiCl2PhNC(Ph)CH2P(Ph2)N(8-C9H6N)}] (9)。Ph2PCH2P(Ph2)N(8-C9H6N)(10)与(DME)NiCl2的类似反应生成五配位的N,N,P-螯合镍配合物[NiCl2Ph2PCH2P(Ph2)N(8-C9H6N)}] (11)。[(8-C9H6N)NP(Ph2)]2CH2(12)[由(Ph2P)2CH2和2当量的8-叠氮喹啉制备]依次与LiBun和(DME)NiCl2反应得到[NiCl(8-C9H6N)NP(Ph2)}2CH] (13)。新化合物通过1H、13C和31P NMR光谱(对于抗磁性化合物)、IR光谱(对于镍配合物)和元素分析进行表征。配合物2a、4、7、9、11和13还通过单晶X射线衍射技术进行表征。这些镍配合物被评估用于芳基锌试剂与芳基氯和芳基三甲基铵盐的交叉偶联反应的催化活性。在催化芳基锌试剂与芳基氯或芳基三甲基溴化铵的反应中,配合物7显示出最高的活性。